<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>keyframes-animation-3</title>
    <style>
        div
        {
            width:100px;
            height:100px;
            background:red;
            position:relative;
            animation:myfirs 2s linear 2s infinite alternate;
            /* Firefox: */
            -moz-animation:myfirst 2s linear 2s infinite alternate;
            /* Safari and Chrome： */
            -webkit-animation:myfirst 2s linear 2s infinite alternate;
            /* Opera: */
            -o-animation:myfirst 2s linear 2s infinite alternate;
        }

        @keyframes myfirst
        {
            0% {background:red; left:0px; top:0px;}
            25% {background:red; left:0px; top:200px;}
            50% {background:red; left:200px; top:200px;}
            75% {background:red; left:200px; top:0px;}
            100% {background:red; left:0px; top:0px;}

        }

    </style>
</head>
<body>

<p><b>注意</b>该实例在Internet Explorer 9 及更早IE版本是无效的。</p>
<div></div>

</body>
</html>